The Science Core B will support activities in all four projects of this IPCAVD Proposal. Core B will be responsible for the production of protein reagents and vaccine immunogens that will be used in Projects One, Two, and Three. Core B will be responsible for the production of recombinant Envelope proteins for analytical studies in Project One, and the production of the Envelope-based immunogens that will be used in for pre-clinical vaccine studies in Project Two. Additionally, Core B will assist in the development of stable protein production cell lines and analytical validation of stably-produced Envelope immunogens in Project Three.